Originally Posted by pinglow
"They do not know"???
I seen one of two youtube videos even the front LEDs are flashing away when the bike is on the move.
Every LED I've seen does that when filmed, it's not perceptible to the human eye when viewed directly. It's a side effect of a rapidly flashing light source and the frequency of the camera taking each still frame. Kind of like filming a TV gives you visual interference.
This seems to be distinctly different than what the OP is seeing, which sounds more like an intermittent ground or similar